WATER DISTRIBUTION SYSTEM DESIGN REPORT UET LAHORE by envian

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WATER DISTRIBUTION SYSTEM DESIGN REPORT UET LAHORE by envian

  1. 1. REPORT OF WATERDISTRIBUTIO N SYSTEM
  2. 2. TABLE OF CONTENTSPage no.Preface ....…………………………………………………….3CHAPTER 1INTRODUCTION i. Study area ..…………..………………………………... 4 ii. Land use analysis …………….………………………... 5CHAPTER 2WATER DISTRIBUTION SYSTEM i. Basics of WDS ………………………………………... 6 ii. Types of pipes …………………………………………. 9 iii. Basic equations ..………………………………………. 9CHAPTER 3METHODOLOGY OF WDS 2
  3. 3. i. Hardy cross method ……………………………………. 11 ii. Loop software ………………………………………….. 12CHAPTER 4DESIGN OF WDN IN "FUTURE VISION HOUSING SOCIETY IEER UET LHR" i. Design data …………………………………………… 13 ii. Design criteria ………………………………………….. 14 iii. Results ……………………………………………… 15 iv. Comments ……………………………………………… 16REFERENCES ……………………………………………...17 PREFACEThis report is submitted to Assistant Professor Husnain Haider, the sessional report on water distribution system for 6th term .Architecture Engineering This report can help reader to understand the propermethodology of preparing the design of WDS of the housingsociety. Further more there is a brief discussion on efficiency of system, suggestions to make sure the supply of portable water, cost analysis, positive & negative features of system etc. so that every one may understand the whole process easily. In this way I can conclude that it is a complete & comprehensive report in all manner but still comments & 3
  4. 4. .suggestions are greatly welcomed I would like to thank my teacher Mr. Husnain Haider for .guiding me the steps for designingCHAPTER 1 INTRODUCTIONSTUDY AREA:  LOCATION: The housing society (Future Vision Housing SocietyIEER UET LHR.) for which we are requiring to design the "WaterDistribution Net Work " is situated near "Upper Chanab Canal" .  TOPOGRAPHY: 4
  5. 5. The over all surface area of the housing society is FLAT,because the slope of area at almost all the points is between (1% - 2%)Since we can have three types of surface areas; on the basis of theirslopes: 1. Flat Area (slope; 1% - 2%) 2. Rolling Area (slope; 5% - 8%) 3. Steep Area (slope; > 8%)  CLIMATE: Since usually the flat areas have moderate climaticconditions, similarly the area under consideration has.Maximum temperature in summer may range from 30˚C - 45˚C & rainsusually occur in mid July & August. In winters he temperature can fallup to 0˚C, but winter season usually remains for only three to fourmonths.  DIFFERENT USES OF WATER:The uses of water in the society under consideration are: a. Domestic use: Drinking, cooking, washing, bathing, irrigation of plants etc. The range of domestic use can vary from 100 – 300 LPCD1. b. Commercial use: Washing & freezing for cooling purpose etc. usually 12.2 m3/1000m²/day2 water is consumed in commercial areas. c. Public use: School, parks & dispensary etc. Range of water for public use can vary from 50 – 70 LPCD3. d. Fire demand: The total fire flow for a single fire should not exceed 22680 l/min4. e. Losses & waste: Uncounted fall, misuse or wastage etc.LAND USE ANALYSIS: Sr. # Land use Covered area % (m²) 1 Residential plots 32218 60.88 2 Flats 1404 2.65 5
  6. 6. 3 Apartments 4116 7.78 4 Commercial area 482 0.911 5 School 687 1.298 6 Grave yard 276 0.522 7 Dispensary 240 0.454 8 Open areas 2487 4.699 (parks) 9 D.S + T.P 1396.5 2.64 11 Roads 9613.5 18.167 Total 52920CHAPTER 2 WATER DISTRIBUTION SYSTEMBASICS OF WDS:  SOURCES OF WATER SUPPY: a. Surface water sources. 6
  7. 7. b. Groundwater sources. We have ground water source in our society, as we are obtaining water from tube well .  COMPONENTS OF WATER SUPPLY SCHEME: a. Collection works. b. Purification works. c. Transmission works. d. Distribution works. But here in our society, we just have concern with distribution works.  MINIMUM RESIDUAL PRESSURE:It is the pressure required to reach the farthest point in the community.If the pressure in pipes is less than the minimum residual pressure thediameter of pipe is increased, in this way the velocity of waterdecreases & hence the frictional losses decreases, so as head loss.According to WASA-LDA criteria, the minimum residual pressure shouldbe 20psi (or pressure head should be 14m in water supply pipes).  PER CAPITA WATER CONSUMPION:Water consumed by one person in one day is called per capita waterconsumption. Usually it is represented as LPCD (Liters Per Capita perDay) or GPCD (Gallons Per Capita per Day) .  PEAK FACTOR: The ratio of maximum or peak flow to average flow is called as "peak factor".  MAXIMUM HEAD LOSS: The maximum acceptable value of head loss in a water distribution system is termed as "maximum head loss".REQUIREMENTS OF AN IDEAL WATER DISTRIBUTIONSYSTEM: a. To supply adequate amount of water, to completely the need of community. b. To supply water with minimum residual pressure at all points of the community. c. To supply water which is esthetically appealing (tasteless, colorless, odorless) d. To supply water that is hygienic & free from all sorts of pathogens. 7
  8. 8. AVEGAGE WATER DEMAND (AWD):The average amount of water required for a community for its designperiod is termed as AWD.MAXIMUM DAILY DEMAND (MDD):The maximum amount of water required in a day, for a community istermed as ADD.PEAK HOURLY DEMAND (PHD):The calculation of per hour water requirement for a community istermed as PHD.According to WASA-LDA : MDD = 1.5 * AWD PHD = 2.25 * AWD PHD = 1.5 * MDD :Fire demandit is the demand of water required for a particular time whenthere is fire blown at some area. For the fire extinguishing, the waterrequired is to be of high pressure and excessive quantity. For meetingthe fire demand, quantity of water required is calculated from following :formulae F = 18 C A0.5WATER DISTRIBUTION SYSTEM:  Layout: a. Dead end system. b. Grid Iron system / loop network.Dead end system: In this system it is easy to add on and easy to calculate.Advantages: • Require less no. of valves to cut-off supply to the area • Cheap systemDisadvantages: • Stagnation • Larger area is cut-off in case of repairs 8
  9. 9. Grid Iron system / loop network:Disadvantages: • Require more no. of valves to cut-off supply to the area • Difficult to designAdvantages: • No stagnation • No larger area is cut-off in case of repairs  Methods of distribution: a. Distribution by gravity. b. Pumping without storage. c. Pumping with storage.Distribution by gravity: Distribution by gravity is possible only when the source of water is located substantially above the level of the site where water is to be provided. Here we have to rely on the pressures and heads already defined by the elevation difference between the water reservoir and the area which is to be supplied with water.Pumping without storage: It is least desirable method as it provides low reserve flow during power failure. High power costs are required to meet the peak hourly demands.Pumping with storage: It is the most common and the best method of water distribution Water is pumped at uniform rate, supported with the stored water during peak hours. This system is reliable during fire fighting and power failures.  Types of supply: a. Continuous supply. b. Intermittent supply.Continuous supply: In this type of supply, the water is made available to theconsumer throughout 24 hoursa day. :Advantages 9
  10. 10. • Availability of water for fire fighting at any time. • No infiltration of undesirable water occurs. :Disadvantages • More use of water. • Costly method.Intermittent supply:In this type of supply water is available to the consumer onlytwo to three times a day, that means, during periods of high .consumption :Disadvantages • Infiltration of dirty water may occur. • Fire fighting may be difficult. • The meets of the consumer are not adequately fulfilled.TYPES OF PIPES USED IN WDS:Following types of pipes are used in water distribution system: • AC (Asbestos Cement). • PVC (Polyvinyl Chlorine). • GI (Galvanized Iron). • MS (mild Steel). • Concrete pipes. • Iron pipes.BASIC EQUATIONS: a. Mannings equation: V = 1/n R2/3 S1/2 Where: V = velocity n = Mannings roughness coefficient R = hydraulic mean depth / hydraulic radius S = longitudinal slope b. Chezys equation: V = C √RS Where: V = velocity c = chezys roughness coefficient R = hydraulic mean depth / hydraulic radius S = longitudinal slope 10
  11. 11. c. Hazen Williams equation: Q = 0.278 C D0.63 (HL/L)0.54 D2 Or HL = 10.68 (Q/C)1.85 L/(D)4.87Where:HL = Head lossQ = FlowC = Hazen William constantL = Length of pipeD = Diameter of pipeOne requirement should be fulfilled while using above equations isthat, flow should be uniform. Uniform flow means that "fluidcharacteristics should remain same in the section underconsideration." 11
  12. 12. CHAPTER 3 METHODOLOGY OF WDSHardy Cross method is used while designing a WDN.HARDY CROSS METHOD: The analysis of pipe network is done byHardy Cross Method. By using this method, accurate determination offlow rates & head losses through a system cam be calculated.ALGORITHM USED: a. Inflow = out flow at a node. b. Sum of HL in a loop = 0.PROCEDURE: 1. Assume any suitable diameter for network pipe & then assume any internally consistent distribution of flow. The sum of flow entering at any junction must be equal to the sum of low leaving. 2. Compute HL in each pipe by using : 3. HL = 10.68 (Q/C)1.85 L/(D)4.87 4. With due attention to sign compute the ∑HL around the loop. 5. Compute without regard to sign (H/Q) for each pipe in the loop. 6. Find ∑H/Q without regard to sign in each pipe. 7. Find correction using : 8. ∆ = - ∑H/ [1.85 ∑ (H/Q)] 9. Repeat the steps 1 – 7 until ∆ is less than 10% minimum flow in a pipe of the loop. 10. Find residual heads at all points. If residual heads are close to the minimum required residual head, then the design is complete. If the residual head is less than the required 12
  13. 13. minimum residual head then increase the diameter & start from step 1; again. If heads are much higher than minimum residual head then decrease the diameters so that cost would be reduced, & then start the process again from step 1.LOOP SOFTWARE: Loop is a computer program in BASIC for Hydraulic Simulation of Looped Water Distribution Networks.BRIEF HISTORY: • Language : BASIC • Contribution by : UNDP & World Bank • Contribution for: International Drinking Water Supply & Sanitation Decade 1980 – 1991. • Why: Based on the results of a study conducted by WHO & World Bank in 1970s. • 80% of all disease • 60% of child death • Program developed by: University of North Carolina, USA.LIMITATIONS: • Max no. of pipes = 500 • Max no. of nodes = 400 • Nos assigned to nodes = 1 – 36000 • Can handle up to 10 nodes with known HGL ( generally OHRs)EQUATION USED: Hazen William equation is used to find headlosses : HL = 10.68 (Q/C)1.85 L/(D)4.87OUTPUT: • Flow in pipes • Velocities in pipes • Pressure at nodes • Direction of flows • Head losses in pipes etc.UNITS: 13
  14. 14. • Flow = m3/sec • Length = meter • Diameter = mm • Nodal withdrawal = -ve • Pumping quantity = +veNODAL FIXITY: • Pumping source = 1.0 • Network nodes = 0CHAPTER 4 DESIGN OF WDN IN "FUTURE VISION HOUSING SOCIETY IEER UET LHR"DESIGN DATA:No. of plots = 281No. of apartments = 3No. of flats = 3Design period = 20 PRESENT (2011) AT THE END OF DP (2031) Persons per 8 10 plot Persons per 500 700 apartments Persons per 300 500 flatPer capita water consumption = 250 + 10 Y = 250 + 10 (17) = 420 LPCD 14
  15. 15. Design population = Pf = 2810 + 2100 + 1500 = 6410 personsAverage Daily Demand (ADD) = A.W.C * population = 420 * 6410 = 2692200 L/dayP.H.D = 2.25 * A.D.D = 2.25 * 2692200 = 6057450L/dayM.R.H = 14mDESIGN CRITERIA:We have the following combination in our society:  Grid Iron system.  Pumping with storage.  Continuous supply. ⇒ Since we are having with a relatively small housing society. & load of flows on pipes is not much, so we can use pipes with moderately small diameters. Like a. Pipe of 225 mm diameter can be used from OHR to Node #1 as a primary pipe b. Pipes of 100 mm diameter can be used in secondary network c. Pipes of 75 mm diameter can be used in tertiary network ⇒ There must be a minimum earth cover of 1 m, so that there would be minimum affects of load on pipelines. As the affects of load reduces 80 – 90% up till 1 m earth cover. ⇒ MRH: The minimum residual head should be 14m (20psi) according to WASA – LDA criteria. ⇒ We are using AC pipes in our WDS having structural life = 50 years. With Hazen William constant value between 120 – 140 5 . 15
  16. 16. :DISCUSSION OF RESULTS :PIPES DIAMETER OF PIPES NO OF PIPES mm 150 mm 100 1 Maximum diameter = mm 2 Minimum diameter = mm :(PRESSURES (RESIDUAL HEAD 3 Maximum residual head = m 4 Minimum residual head = m 5 Average head = 15 m :LENGTHS 6 Maximum length = m 7 Minimum length = m 16
  17. 17. RESULTS: ⇒ Since velocity in some of the pipes is low than the desired range (0.5 – 2.5 m/sec), but doesnt matter, because velocity is not the design criteria of water supply network. ⇒ Since in some pipelines, the head loss is higher than our restriction (20m/km), but still it cant affect the efficiency of WDN, as the diameters of these pipes are adequate & supplying the water more than the required flow & pressure. ⇒ Since the available heads in all pipelines are much more than required heads (14 m) but are acceptable.COMMENTS: ⇒ Since manual Hardy Cross is very tiresome & time consuming, but by using LOOP software we can calculate flows, diameters & velocities etc. just in few seconds. ⇒ Since we are pumping water from ground using tube well, therefore there is no need of water treatment plant, but the laboratory tests of water should be carried regularly & proper disinfection of water should be done to insure a supply of potable water. ⇒ Since we are using AC pipes which have structural life up to 50 years & the design period of our society is 20years, it means at least up to 20years after the full development of society, we dont have any need to replace new pipelines. ⇒ Since we are having a Grid Iron system, this means that stagnation of water does not take place as more water comes from more than one direction. 17
  18. 18. REFRENCES: ⇒ 1,2,3,4,6 "Water Supply & Sewerage" by "E.W.Steel", TERENGE J.M C G H E E 6TH EDITION ⇒ 5 "Water Works Engineering" (Planning, Designing & operation) By "Syed R. Qasim, Edward M. Motley, Guang Zhu” page#166 18

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